Production of metal carbonyls



L. SCHLECHT El' AL PRODUCTION OF METAL CARBONYLS Dec. 26, 1933.

Filed April 4, 1951 Fi S 2 CARBON MONOx/OE 2 Sheets-Sheet l BYZLez'rATTQRNEYS fv/7% PWM Dec. 26, 1933. L. SCHLECHT Er A1.

PRODUCTION OF METAL CARBONYLS Filed April 4, 1931 2 Sheets-Sheet 2 IRONCARBONYL WASTE GAS Fig@- CARBON OXIDE Q Ul.. R .I L ENUHY moNX oPou CmnNOZZLE CA RBON MONOX/ E IRON SUSPENDED /N IRON CARBONYL CA R BONYLINVENTORS Leo SczZeczZ max naumann M BYE/mr ATTORNEYS MP W willMATER/A1. FORM/NG CARBO/VYI. v

CARBON MONOXIDE Patented Dec. 26, 1933 A UNITED srATss l1,941,111PRoDUofrIoN'oF METAL oARBoNYLs Leo ySchlecht and Max Naumann,Ludwigshafen-d.

on-the-Rhine,.r Germany, assignors to I. G. VFaibenimdiistrieAktiengesellschaft, Frankforton-the-Main, Germany Y lAppinmif'mApril 4,1931, serial No. 527,650, and

, Y in Germany April 7,1930

1i) Claims. (Cl. 23;-203)v The present invention relates to improvementsin the production of'metal carbonyls andvto improved apparatus therefor.

Metal carbonyls are preparedv by acting with carbon monoxide or a gascontainingl carbonv monoxide on a material comprising a metal capable offorming a metal carbonyl, usually at elevated temperaturesand'preferably under high pressure. If this process is carried out on anindustrial scale, it is essential to obtain good yields per unit of timeand space, since otherwise the reaction requires much time and verylarge and consequently expensive apparatus.A It is also important toprevent `inconvenience by reason of the decomposition of carbonmonoxide, and With this object in view it is of particular importance,especially When Working under pressure, to lead away the considerableheat disengaged by the reaction and rapidly and uniformly'to obviate anyiiuctuations in temperature, even if they are only local fluctuations,temperature in thel reactionV vessel, use maybe made of special heatingand cooling devices, such y as coils or jackets, but these have thedisad-v vantage that their action is'slovv and not sufficiently uniform,thatthey require space Within the reaction vessel whereby reactionspace' is lost which is particularly inconvenient Wheny Working underpressure, and that they render it difiicult to iill thereaction vesseland, in continuous operation, to pass the reacting materials through thevessel.V Moreover, it has been observed that, When introducing thecarbon monoxide into the reaction vessel by meansof only one passage andalso withdrawing itV therefrom by only one passage, the carbon monoxiderapidly reacts with the metal in the neighbourhood of the gas inlet, butthat its action decreasesvery soon, due. -to the equilibrium beingattained; therefore large amounts of gas and carbonyl vapor must'beconveyed through a large portion of the reaction vessel 'Without anyfurther forma-k tion of carbonyl taking place; in consequence of thisphenomenon it takes a long time until thev metal in the neighbourhood ofthe gas outlet enters into reaction.

We have now found amethod of' Working by which the aforesaiddisadvantages are overcome at least to a great extent, so thatthe'process can successfullyV and economically becarriedout on a 'largeindustrial scale. In the process 'according to the present invention useismade of a iiuidk Vconveyed through the reaction vessel which issupplied into, or Withdrawn from, or both sup-l plied into and withdrawnfrom, the reaction In order to control the kiiuid independently 'of eachother.

in Vthe dry state.

vessel at'several places which are distributed preferably in severalzones over the Whole space within the reaction vessel. V The saidv'fluids may be either gases or liquids. When gases are employed as thefluids, use is preferablyY made of the reaction gas itself, namelycarbon monoxide ora gas containing the same. Use may also bemade'of'inert liquids or melts, as for example organic substances, suchas oils, paraffin Wax and other hydrocarbons, or any other liquids whichunder theV workingV conditions f `(concentration, pressure andtemperature) employed do not substantially attack in an obnoxious mannerthe carbonyl forming material, the carbon monoxide and the carbonylformed, vv may be employed. Liquids having high specific heats, as forexample Water, are especially suitable, as are also liquid or fusedmetal carbonyls. If desiredjcarbon monoxide is dissolved in theseliquids beforehand. y It willbe readily understood from the foregoingthat the apparatus used according to the present inventionj consists ofa suitable reaction vessel having a plurality of inletland/or outlet"devices for the fluid, which are `preferably distributed 1h80 theinterior of the reaction vessel not onlyl over the lengththereof butalso over the cross-section thereof and are preferably constructed sothatY theymay be supplied.V with differing amounts of The number andspecial construction of the inlets and/or outlets may bel diierent atdifferent parts of the reaction vessel.y They dependen the size andvshape ofthe reaction chamber, on the nature,

especially the reactivity, of the initial materials 9@ and on theWorking conditions employed, as for example Whether the initialmaterials are treated with carbon monoxidein the dry state or in thepresence of liquids. Thus, inthe latter case a smaller number of gassupplies is as arule suflicient, than when treating the vinitialmaterials The nature of the apparatus used according to the presentinvention Will now be further explainedV with reference to theaccompanying Sdrawings which illustrate diagrammatically arrangements ofapparatus suitable for carrying out the invention, but the invention isnot restricted to these arrangements.

When using carbon'monoxide as the fluid,'the 105 simplest method is toemploy a single pipe passed through the longitudinaldaxis of thereaction vessell and provided with openings or no'zzles'the size ofwhich is selectedaccording to the amounts of gas toV be'su'pplied to thesingle zones of the rell() ,i6-tion chamber l, especially in the'lohgeD' 3 through which carbon monoxide is introducedY into the vessel. Thegas and the carbonyl vapors formed-are Withdrawn from the-reactionvessel by a pipe 4. Instead of the perforatedtube shown in the drawings,use may be made of a 10 porous tube made for example by sinterng copper"powder or glass powder.

In order to be able to supply the single sections of the reaction Vesselwith` regulatable, different amounts oi gas independently of each otherseveral inlet openings, and-preferably'also'outf lo let openings, may bedistributed at intervals in" the Wall of the reaction vessel overfthewhole surface thereof. Distributors or nozzles in the interior of thereaction vessel may be connected to the said openings if desired. Orseveral inlet and/or outlet pipes may be arranged within the "freactiofnvessel. An apparatus of this kind is shown in vertical section inFigure2 and in crosssection in Figure 3; A reactionvessel l of cirgg'icular'cross-section has two covers 5 each profv'idedwithl three openings 6 towhich pipes 2 inr Y,

flthe interior of the reaction vessel l are connected. 'f The pipefsZserve for the supply of gas, are ca- "pable of being closedindependently by valves and v'aref all fed through pipes 7 by thecirculating 'pumps and fresh gas pumps. They project dif- ","ferentdistances into the 'reaction vessel, are "closed at their inner ends andare provided with a 'largejnumber of openings or rnozzles at thel"places atwhich the gas is to flow out. The withf drawal of the gasesiseifected through pipes 4; lThis arrangement, which has the specialadvan- `ftage' that the inovving gases, which are usually "fjcool,are'heated'up'before they enter the reactubes 2, l is suitableveitherfor working in the presence of fliquid's, as' for `eifzample inVcontinuous operation, [for for Working with gaseous carbon monoxide and"reaction material in the form of pieces'. In the former casethe'loweroutlet at 4 is dispensed with andnone of the pipes'2 should bequite free from waicurrent of gas at vany time so that clogging of,

ljjthe'nozzles may be avoided.

It isalso possible toso modify this arrange-V 5@ Y Inent that the gas issupplied from the axis of the reaction vessel. In this case severaltubes are arranged concentrically one inside another in theflongitudinal axis of the reaction vessel, thedisv 'tribution of gasAover the' cross-section of the reactionl vessel vbeing eiected by adevice of the jnature of a ring,v burner or by nozzles. vThe j nozzlesmayhave such aj'size and shape Vthat the "gas is introduced under acomparatively high pressure and with a high speed, thereby being 6;Supplied to a substantial portion of the reaction 'jspace. The nozzlesmay be arranged on one "side'only oi the supply pipes, or they may bevdisy, tributed more or less uniformly over thewhole surface'of the saidpipes. When arranging there.;v

on .one side'only of the' supply pipes and when 'the contents of thereaction vessel are in the liquid or pasty state, the said 'contentsmaybe `@moved b y the gas introduced. Alternatively, when Ythe `supply,vpipes are Yarranged inOVably, A, they may be caused to move, forexample to roate, bythe gas; The aforesaid arrangement of "i-,hggassupply pipesin the centre of the reac` 'tion' vessel Vis'illustrate'din Figure e, the vessel ti", itself not being shown Aforv thesake (if`greater clearness. Figure 5'illustrates a view of the de" ing too'rgreatly diluted.

vterial in Ylump form. Carbon monoxide is lintroof a number of pipes 4.

ras liquid metal carbonyl, and in which not only thecarbon monoxide issupplied at several places of Vthe'reaction Vessel, but also the liquidmedium is-introduced vatseveral points. As illustrated in thelsaid gure,a high pressure vessel l is lled with asuspension of iron in ironcarbonyl. Carbon monoxide is introduced into the vessel under a pressureof 200 atmospheres by means or" pipes 2 provided with control valves 8.The gasesV Vleave `the reaction vessel by means of a pipe andthen ypassthrougharcooler 9. Theliquid iron carbonyl separated therein. may bereturned finto the reaction vesselto theextent necessary with regardtothe temperature inthe reaction vessel by"means of'pipes le providedwith control valves l1. 'Theremainderof the liquid carbonyl is: removedfrom the cooler by ico Hway of a pipe l2 andadischarge valve 13. The

4arnountvofgassupplied into the vessel is proportioned sothat'suiiioient carbonyl is vaporized to prevent'the paste Within thereaction Vessel be- In the'apparatus shown in Figure 7, the highpressure vessel l is'supplied with initial inaduced by means oftheporous tube 2L The gas containing carbonyl vapor is withdrawn by`means It will now be readily understood that the apparatusdes'cribed inthe foregoing yare only typical examples, and that'the constructionaldetails may beA modified in'v many respects Without departing from theAscope of the present 'invenn tion. L

The process according to the present'inventure of 'metal carbonyls.

Y'Thus, when supplying the carbon monoxide, Whether" as such or in theform of a solution in a suitable liquid, inthe manner hereinbeforespecined the reaction proceeds practically l'uniformly throughout thewholereaction space, so Vthat the throughput 'in' a vessel of given sizeis much greater than when supplying the carbon monoxide by ya; only 'oneinlet at one side of the reaction vessel and withdrawingit by only one:outlet at the other side, as has been hitherto usual.

Furthermore, the use of the fluids in the manner specified 'renders itpossiblelto effectively control thetemperature at each placeY or zonewithin the reaction vessel, by suitably varying the 'amount andtemperature of the iiuid supplied' to each zone.

. Thus,- if a gaseous'iluid, for example. carbon monoxide is used, andif for example the temperature in one or more zones of the reaction sie,

4spa'ceistoo high, the reaction gas is supplied to the said zones with asuitably rlower temperature and rin an appropriate amount; the gas isheated within the vesseLthereby cooling the latter, V'and after leavingthe vessel it vis passedV through 'a ysuitable cooler, where it iscooled to the desired temperature', and is' then reintroduced into thevvessel in 'a circular'course, preferably without the fluids, Vthese areemployed ina similar ,man-4 advantagenot only to'distribute the inlets,and if Especially 'for the lpurpose ofA cooling, other inert gases, aslfor examplehydrogen', nitrogen and carbondioxide', may be' employedinstead ofthe reaction gas; in this case the cooling action isparticularly-strong, because-the reaction gas isf diluted and thereaction thereby retarded, `so thatl less heatfisdisengaged.yvWherusing-liquidsas Contrary to expectation; the yields iper unit oftime and space do not suffer byworking inthis manner, butareconsiderably improvedby reason of `the rapidv and uniform regulation ofthe temperature. vThe difference'between the temperau Y' ture` of the,`gases ror liquids'- and'the temperature' jsuit the requirements. Inorder lto avoid considerable speeds of flow inf the reaction'fvessel, vn

'of cooler may be employed for the condensation of the reaction vesselmay-be'readilyiadapted to the said difference in'temperatureis'advantageously chosen'fairly great; ythe difference is media maybe atdifferent temperatures and vatVV Y limited Vhowever by Ythe facts that*at'too' high of the carbon" temperatures decomposition monoxide-takesplace and that-there'is a n.danger- -that the cold gas'or liquidintroduced may bring the reaction to a standstillr first at the inletand then throughout the reaction vessel.-

Of course, the different "currents ofV flowingdiiierent speedsindependent'of each other. -In

Vthis manner the "danger `rthat' the contents of the reactionfvessel-maybecome too cold or too hot locally is to a large extent vavoided so thatthe fluids in thisv caser-nay even lie-strongly cooled for example, andeach zone of the reaction space may be heated or cooled asA desired,independently iromother portions of the reaction space.- The Y viiuidsmay be introduced'for exampleby means of a pump.

Before their entry into the reactionvesseLliquid -fluids vare-preferablymore or less` saturated with carbon monoxide, advantageously 'under the'pres-v sure prevailingin the-reaction.vesselyand this is especially tobe recomended when-employing by the evaporation Y liquid or fusedcarbonylsas the-.liquid-'i'lu-ids inl` order to avoidV decompositionvThe liquid iiuids introduced for thepurpose ofcooling may be more orless completely converted into the vapor rare preferably condensed againat a suitable placev outside the reaction vessel and may bereturned"` toythe reaction vessel when desired.

The following example will vfurtherV illustrate the employmentofvaporizable liquids as the ow- H-ing"m'edia, but the'mode of operationis notre--l stricted to this particular example.-

Carbon monoxide is caused to fflcw under pres` sure upwards through 1` avertical high 'pressure vessel filled with a s uspension of iron in ironcarbonyl.

The vessel is 'provided with a reux condenser in which the Ycarbonylvaporcarried alongby theescaping current of gas is more orl lessliquefied, depending-on the' 'cooling temperature inthe condenser, andfrom which'the liquefied carbonyl iiows back '-cooledinto' thef'vessel.yyThe reiiuxed carbonyl Vis introduced intof-the" ves-f sel at different'place'sf througha number "of sub# mergedwpipes, whichifdesired"maybeclosableI by means of Valves. It is not necessary-however;

to return'the whole ofthe carbonyl liquefiedin the reflux condenser tothe reaction vessel for cooling purposes. In this case the coolingtemperature in the condenser may be kept continually constant becausethe amount of carbonyl desired also the outlets, for the liquidthroughout u thevessel butv also to provide forseveral inletsandfoutlets for the gas.I In some cases the vaporization may beeiectedso rapidly that the liquid introduced isimmediately convertedlinto the gaseous or vaporous phase and the liquid a's such is onlypresent atfthe most for only a short time inthe vessel. f Instead of areflux condenser, any other kind of the liquids vaporized in thevessel.' In cases when the introduction of the condensed carbonyl l orother'liquid employed cannot'be carried out directly, as for examplebyreason of diierence inY level, it may be-efiected by means of a pump.In? any case it is advantageous that the liquid 'serving forcoolingor'heating should remain within the reaction systembecause it isthen al- Ways 'saturated with the reaction gas and does not have to bebrought to the reaction pressure.

' Y Instead of or in addition to vaporizable liquids,

diicultly Volatile liquids may be employed, or a part only`of vthevaporizable liquid may be vaporized. The liquids as for example oils,carbonyls' inthe liquid phase and the like, or'the pastes consisting' ofthe liquidsconcerned and ne-grained materials capable yof forming car-'bonyls,'are preferablyl led in circulation, without 'releasing thepressure,'on ,the one hand through the vesselcharged with thereactionmaterial and `iorrthe otherhandl through a `suitably eicient heatexchanger.

With' theaid ofv distributing means for the introduction and/orwithdrawal,

Iany desired amountof liquid may beallowed to enter Vanyfpart of thevessel whereby a particularly intensive cooling or heating effect isbrought In many cases Hthe circulationr may be about. effectedwithoutAspecial driving means, in that the liquidbecomes heated inlthe vesseland ascends therein, passes to the cooler, 'sinks therein A by reason ofthe increase in specic gravity caused by the cooling, and enters thevessel again. YIn

-heatingproces'ses the said circulation takes place -inthe oppositedirection. 1 i A /Iti's'particularly advantageous the process accordingto the` present invention to combine the temperature. control by means.of Vliquid iluids with that by means of gaseous media.

f The heat withdrawn from the reaction chamber bythe fluids ispreferably taken up in a" suitable manner in appropriate apparatus andrendered useful, as for example forthe production of high pressuresteam. 1 e

' A special advantage of the process according to the present invention`consists in the fact that the apparatus which serve for the absorptionof the vheat isto be`withdrawn or for the supply 'of `rthe iheat to besupplied may be more ory less spatially separated from the apparatusserving for the formationof carbonyl and not combined v"therewith as inother processes in which a cool- .,ing apparatus-isfarranged ont,l or inthe'reaction Vessel.

,5 whereby the utilization of the heat, as forexamplethe production ofhigh pressure steamwith the employment of the counter-currentprincipleapparatus the outer cooling orheating vmediumvails in the apparatusitself so that onlyy'thinv separating walls are necessary@ For-example`when Working under a pressure of f200 atmosj` pheres the cooling. wateris pressed throughthe may be utilized in the thermal ldecomposition ofmetal carbonyls for preheating-the heatingfgases yand for vaporizing thecarbonyls as well as in thefurther working` up ofthe metals therebyobtained. [Fon example -cold liquids may beY passed through the reactionchamber for removi f ing-heat therefrom'andwithdrawn inftheyhot `Theliquid carbonyl in a hot state, if; desired superheated, lmay* be led'for example *tol *thej vaporizer of the decomposition apparatus for i-:producing free metals from the carbonyl'so that it need not further beheated therein. A1 particugases are employed directly as such; as foreX-gr ample when hot carbon monoxide visto-be led-into devices while theliner regulation'ofrtemperature (Tix action gases.

chambers and the like.

The -cooling and heating of the luidslmay be-V effected in the usualmanner. In some cases it isfperatur-,e-of theuid lfor each Z011@-advantageous to withdraw thefluds to be em ployed from' other reactionvessels orsystems K i actingf With-carbon monoxide in aconfined re- Yserving for the preparation ofl carbonyls. Thus for example forl heatingthe carbonyl-forming material, the Ahot liquidsfrom a reaction vessel;yin'vfull operatiolrnay be led to the carbonyL. f forming material`whereby the latter is -v heated and the liquids whiclrhave thusbeen-cooledlrnay; then be returned to'the'reaction vesselin ordersasesrfoli purposes; -v ll 1e process according tothe present inventionis ofparticular advantage-.when vfused in con- -n ection,withreactionfvessels vin: whichthe mean The heating and cooling devicesarethen preferably so arranged that single Zones.,v of the reaction vesselmay be influenced'indee. ,pendentlyof each other, as for example by pro-4viding -several separate pipe systems, lcooling.;

In :this manner. the apparatus which serve to take up the heat ofthelowingmedia I leaving the vessel, may have Va constructionv asHsuitable as possible for the withdrawal of fheatl,. f.

. ope ating Aseveral -reactionvessels simuly,

ianeusl'vit lsalse'advantageous i0. C 'the hoi' A gases o f 0neVreaction vessel by means ofthe cold is considerably facilitated. Inorder to facilitate thetransfer of heat in the cooling or; heating.-10H- ymay be employed under the pressurefwhich pre- -y gases.Qfangihefreacticn ,v eSSl.- wherebrftlieheat requirements@from.reaction-fresse -arsfsupplied action vessels may also be arrangedone behind thethertheyhot gases from lone vbeingpassed f-.erample lwith, inert gases which .displacei 95 thejvreaction'gases andthereforeare capableof removed.Y or which, 5 together Vfwitli the`reaction afrnixture whichisfsuitable 'for othe1.v

diameter isjonly .fsmall as -fompared withf the-M105 lengthoi-thefvessehwsuch vessels-may have a lengthfwhichis forfexample 10 or20 orveven `moretimes as great as -their mean-diameter.

state, and their contents of heat mayfthen be utilized in the saidprocesses which u se'upfheat.

Theffeatures according to ythe-present invenof operationwvherein theinitial material is; con-v veyed through n yplurality of reactionvessels @flanged in :.SleSf i 1. In thegproduction of action space on a.materialcomprisinga Vmetal capable ofciorining; a carbonyl, thestepsfwhich v:comprise.Y supplying alfluid 'into,- and withdrawthehollow space of the `vessel in which the decomposition of carbonyls iscarriedout, incthatthe hot gases are Withdrawn from the container,v in,which the' formation of carbonylftakes-placefand are supplied directlyfor the desired-purpose;- i 50 f placein afpluralityyotzones-of saidreaction space.

2;. Inl'theqproduction cia3 metal carbonyl by acting withcarbonjmonoxidein va confined re- In some cases't may be preferablenot to-effectf thetemperature regulation solely by fluids, namefY :ly gases or liquids orboth, but to use special= Y'cooling and heating devices, such as-spra1S,;f pipes, jackets, ribs and the like in conjunction.` Ztherewith. For example the more-intensive reguf lation Yoftemperaturemay be ,effectedwith-isuch;

ingplacein a plurality of zones of saidreaction -.spaee-andwith aregulableamount of thefluid l for eachgzone.

3. In theproductioii of a metal carbonyl by actngj Withc arbon monoxidein a confined reaction space on ai material `c omprisingr'a` Inetalcapable otiQrming--a carbonyl, thestepsfwhich. comprise supplying afluid into, andwithdrawing i t fromgfsaid reaction ',space, at leastoneoisaid 1steps Vof supplying and withdrawing# takingplaceina plurality ofzones of-said reaction space and-with aVv regulable amount and-tem# 4. Injthe production of ya metahcarbonyl by 4)supplyingtakingfplace in aplurality of--zrones of ysaid .reactionispace y l a metal carbonylby:}15 actingwithcarbonmonoxide inra confined re lll() the uid is a gas.

7. The process as claimed in claim 1, in which the uid is a gascomprising carbon monoxide.

8. The process as claimed in claim 1, in which the fluid is a liquid.

9. The process as claimed in claim 1, in which the fluid is a liquidmetal carbonyl.

- 10. The process as claimed in claim 1, in which the material actedupon with carborimonoxide comprises iron.

' LEO SCHLECHT.

MAX NAUMANN.

